If only the rocks could talk…er.. could play a symphony, this is what it would sound like. In honor of the Geological Society of America’s 125th Anniversary, Boulder based-composer and geologist Jeffrey Nytch was commissioned to compose a new symphonic work called ‘Formations’. Mr. Nytch expresses his deep passion for Colorado’s geology as the inspiration for his work in 4 movements. You can read more about this amazing intersection of inspiration, music, and earth science at the Boulder Philharmonic’s website. I owe a debt of thanks to artists like Jeffrey for expressing our natural world in new and exciting ways.
The NASA satellite AQUA captured this October image of eastern Pennsylvania and its rusty brown-colored ridgelines of the Appalachian Mountains. The NASA website also shows a comparision with the same view from the more ‘summery’ September. Here in in the Colorado Rockies, we enjoy similar October colors at ground level- albeit with less color diversity than our Appalachian counterparts. Aside from the season, what ties both images together are the nature of the ridges- parts of folded mountain belts of different ages. The vegetation here in the foothills of the Rockies flanks the sandstone ridges. In Eastern Pennsylvania, hues of gold, yellow and red deciduous trees cover the ridges. Now to totally confound it all, the age of the Colorado rocks are Pennsylvanian in age.
The video of road damage along Highway 34 from Loveland to Estes Park is amazing. The road was reinforced after a deadly flood in the summer of 1976 that killed 143 people in this canyon. Now, almost a week after the 2013 flood, river waters are receding to reveal destruction among 17 counties- both in the mountains and on the high plains. So far nearly 19,000 homes have been damaged, and over 1,500 have been destroyed. The Colorado Department of Transportation estimates that at least 30 state highway bridges have been destroyed and an additional 20 are seriously damaged, with repairs for damaged bridges and roads expected to cost many millions of dollars. Canyon cutting in the age of human settlement is expensive and deadly.
A few observations about our current Front Range flooding. First, the rain is welcome as the area is still in a moderate drought condition but wow, enough is enough! I measured well over 4.5 inches at my house but south of here- in the Boulder-Longmont area, a few observers reported in excess of 14 inches over the duration of the storm. Second, all the rain was accompanied by mild temperatures and little or very light winds. Not much in the way of downed power lines- though power and cell service were knocked out in many places. Folks from the East or Gulf Coasts who are used to September tropical storms must think it a bit strange. Third, and most meaningful to me are the violent bursts of water rushing down our mountain-front canyons, doing exactly what they do (geologically speaking)—vigorously eroding the land. Unlike historic flood events I can remember, this storm is quite regional, impacting the entire Front Range of Colorado, a corridor of about 150 miles.
Big erosional events like these make me appreciate the power of moving water. The origin of canyons, such as those along the Front Range, are easier to understand if you do the math…. 1 meter of erosion every 1000 years (if this is a true 1000 year storm) in a million years equates to roughly 1,000 meters or more than 3,000 feet of downcutting. Of course, downcutting is an everyday event combined with the fact that the Rockies are still slowly rising albeit at a much slower rate. And, if you’re wondering, the Grand Canyon is about 6 million years old.
Debris flows are a type of landslide where a liquified jumble of earth and plant materials form a fast moving mixture following a rain event, dam breach or rapid snow or glacier melting ( from a volcanic eruption, for example). Here, people anticipated the flow along a dry creek bed and essentially ‘chased’ the event down as a storm chaser would track down severe weather such as an outbreak of tornadoes. Is this safe?…not at all! but what’s so eerie is the way the flow occurs well after the rain storm. This reminds me of the way tsunami waves devastate coastal areas, many hours after large submarine earthquakes generate their initial jolt.
Oh my! A new subduction zone is discovered off the coast of Portugal. What does this mean? For fans of Plate Tectonics you can expect the Atlantic Ocean to close- bringing together the North American and European Plates. Don’t hold your breath…the process would take 200 million years.
We recently learned about the specatular encounter between us, Earth, and an object from deep space. In our lifetime, this is indeed a remarkable event. Yet, all we need to do is gaze up at the Earth’s moon (or look at photos of other moons in our own solar system) and its surface is pocked with the evidence of innumerable such encounters. In fact, science has overwhelming evidence that a similar but vastly more violent encounter occurred on Earth 65 million years ago. This is referred to as the Chicxulub Crater in an area straddling the present day Gulf of Mexico shoreline north of Mérida. Unlike the reported SUV-sized object that exploded above the Russian Urals on February 15, 2013, this ancient collision was thought to have been the size of Manhattan Island. Scientists believe its devastating effect on global climate caused mass extinctions including those of the dinosaurs. Asteroids and meteoroids are common place in the space environment but we are thankfully protected from most of them by our gas-rich atmosphere. We also are grateful for the astronomers who keep a watchful eye on large objects, say larger than a football field, whose impact with a populated area on Earth would be disastrous. Next time you wish upon a ‘shooting star’, or gaze at our cratered moon, know we are lucky to be living on this protected third rock from the Sun!
A fun day in the field is second to none. Thanks to all participants for being so curious and allowing me to guide your time travel spanning no less than 18 million centuries. Gives new meaning to the word ‘event’.
A 300 million year old version of the Poudre River
Learning about geologic maps
Say it carefully…Garnet Mica Schist
And you believe this guy?
Inside the Bellevue Dome
And it was a beautiful fall Colorado morning.
What is the “Great Unconformity”?
Thanks to Dr. John Ridley of CSU Geology and our intrepid Northern Colorado Geology Group, we braved cool temperatures and rain to learn more about our local geology. So, what exactly is the Great Unconformity? Not-fitting-in is partly the answer. In geology-speak, an unconformity represents a break in the geologic record of earth history. Here in the Front Range of Colorado, we live minutes away from this amazing geologic feature- namely the contact between 300 million year old Fountain Formation (red, horizontal strata) and the underlying nearly vertically tilted 1.7 billion year old Precambrian schists and granites. Although sporadically visible in places along the Front Range, the Great Unconformity is beautifully exposed west of Loveland near Pinewood Reservoir.
What always amazes me about this is the story it tells about a very ancient mountain range (1. 7 billion year old schists and granite) whose surface was reworked by 300 million year old rivers -now red sandstone). Although the time interval between these 2 events is still over 1400 million years, we can unravel what happened with astonishing clarity right here! Geology is as much about what is left behind as is what is missing. In this case– a lot! That’s what unconformities are all about- missing pages of earth history. So, next time you’re hiking in the foothills see if you can predict where this contact occurs. Or if you’re attending a show at Red Rocks- come early and take a few minutes to visit the Precambrian-Fountain contact which is marked by a plaque behind the amphitheater. Unconformities rule!